Biodegradable IPNs based on oxidized alginate and dextran-HEMA for controlled release of proteins

Alginate is a natural polysaccharide that is widely used for biomedical applications because of its biocompatibility and ability to form hydrogels, but its slow and uncontrollable degradation under physiological conditions represents an undesirable feature. To introduce hydrolytically sensitive sites in alginate, this polymer was partially oxidized using periodate. Alginates with different extent of oxidation were characterized for their degradation behavior and ability to form gels in the presence of Ca(2+) ions. The obtained results showed that the oxidized alginates were indeed degradable under physiological conditions (pH 7.4 and 37 degrees C) and that their gelling ability was preserved for samples with oxidation degrees up to 5%. IPNs, based on oxidized alginate (1% and 5% oxidation) and dextran-HEMA were prepared, characterized and evaluated for protein release. These IPNs showed properties similar to the IPNs networks composed by native alginate, confirming the suitability of IPNs based on dextran-HEMA and oxidized alginate as in situ forming protein releasing hydrogels. (C) 2011 Elsevier Ltd. All rights reserved.